Method for treating neurodegenerative disorders

ABSTRACT

The invention is directed to a method of treating a neurodegenerative disorder in a subject in need thereof which comprises administering to the subject an amount of a compound effective to inhibit the interaction of amyloid-beta with alpha-7 nicotinic acetylcholine receptors.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority from U.S. provisionalapplication Ser. No. 60/087,577, filed Jun. 1, 1998, the contents ofwhich are hereby incorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention provides a method for treatingneurodegenerative disorders. More particularly, a method for treatingneurodegenerative disorders (e.g., Alzheimer's disease) by inhibitingthe interaction of amyloid beta with alpha-7 nicotinic acetylcholinereceptors.

BACKGROUND OF THE INVENTION

[0003] Neurodegenerative disorders such as Alzheimer's disease (AD) andParkinson's disease (PD) afflict humanity with great suffering andfinancial loss. AD is characterized by neurofibrillary tangles, neuriticplaques, and neuronal cell death. AD appears as either the familial,early onset (<60 yrs) or late-onset (>60 yrs) forms, with the latterbeing more prevalent. AD is the major cause of age-related dementia andcognitive impairment (Wisniewski, T.; Ghiso, J.; Frangione, B.Neurobiol. of Disease 1997, 4, 313-328). The amyloid precursor protein(APP), β-amyloid₁₋₄₀ (Aβ₁₋₄₀), and β-amyloid₁₋₄₂ (Aβ₁₋₄₂) are keenlyinvolved in the pathology of AD. The Aβ peptides are derived from APP byproteolytic processing. Dramatic evidence implicating the Aβ peptides,particularly Aβ₁₋₄₂, in AD comes from various recently identifiedmutations accounting for certain types of inherited AD. Such mutationsin the presenilin (PS1 and PS2) genes are probably the cause of the mostfrequent form of familial, early-onset AD (Rogaev, E. I. MolecularBiology 1998, 32, 58). In these cases, as with APP mutations, moreAβ₁₋₄₂ is observed relative to Aβ₁₋₄₀. Extensive studies have shown thatAβ₁₋₄₂ has a greater ability than Aβ₁₋₄₀ to aggregate into the amyloidfibrils that constitute the plaques characteristic of AD (Lansbury, P.T., Jr. Accts. Chem. Res. 1996, 29, 317). Even though Aβ₁₋₄₀ isgenerally present to a much larger degree in the cerebrospinal fluidthan Aβ₁₋₄₂ , it is Aβ₁₋₄₂ which is the major Aβ peptide found in ADplaques.

[0004] The Aβ peptides can inhibit cholinergic neurotransmitter functionindependent of neurotoxicity (Auld, D. S.; Kar, S.; Quirion, R. TrendsNeurosci. 1998, 21, 43). Aβ peptides bind to a number of naturalsubstances such as apoE3, apoE4, apoJ, transthyretin, and albumin. Inaddition, Aβ has been reported to interact with a membrane-boundreceptor for advanced glycation end products and to the class Ascavenger receptor (SR) associated with the production of reactiveoxygen species. Stimulation of the alpha-7 subtype of the nicotinicacetylcholine receptors (nAChRs) can protect neurons against Aβcytotoxicity (Kihara, T. et al. Ann. Neurol. 1997, 42, 159). Also, a setof compounds that activate nAChRs, especially of the alpha-7 subtype,have been found to have in vivo activity in models of cognitionenhancement (U.S. Pat. No. 5,741,802, issued Apr. 21, 1998).

[0005] We now describe specific binding of Aβ₁₋₄₀ and Aβ₁₋₄₂ to thealpha-7 subtype of nAChRs. This new finding has broad ramifications forthe etiology and treatment of AD. nAChRs are members of the ligand-gatedion channel family and appear to be formed from five protein subunitsassociating together around a central pore (Lindstrom, J. MolecularNeurobiology 1997, 15, 193). These subunits include α1-α9, β1-β4, γ, δ,and ε. The α7 subtype forms functional homomers which bind toα-bungarotoxin, a 75-amino acid peptide, with high affinity (0.65-1.7 nMK_(d)) and nicotine with relatively low affinity (ca. micromolar K_(d))(Holladay, M. W.; Dart, M. J.; Lynch, J. K. J. Med. Chem. 1997, 40,4169).

[0006] Compounds which block the aggregation of Aβ peptides arepotentially useful drugs for the treatment of AD. For example,rifampicin inhibits Aβ aggregation and neurotoxicity and may show aneffect in vivo in diminishing plaque burden when compared withage-matched controls (Tomiyama, T. et al. J. Biol. Chem. 1996, 271,6839). In order to block the interaction of the Aβ peptides with α7nAChRs, compounds can be found to either bind to α7 nAChRs, to Aβitself, or to both. Any of these mechanisms of action would be expectedto provide significant protection against Aβ-mediated neurotoxicity andinhibition of cholinergic functioning mediated by nAChRs and beextremely useful for the treatment of AD. The binding of Aβ₁₋₄₂ toalpha-7 nAChRs provides a seed for crystallization or deposition of Aβinto insoluble deposits, which have the potential to grow into thefibrillar amyloid deposits characteristic of AD. Therefore, blocking theinteraction of Aβ₁₋₄₂ with alpha-7 nAChRs should reduce the amount ofinsoluble aggregated Aβ that is formed, and thus prevent theneurotoxicity and pathology associated with such aggregated amyloiddeposits.

[0007] Accordingly, it is an object of the invention to provide a methodfor treating neurodegenerative disorders by inhibiting the binding ofamyloid beta peptides to alpha-7 nicotinic acetylcholine receptors. Itis a further object of the invention to provide a method for treatingAlzheimer's disease and/or for slowing the progression of Alzheimer'sdisease by inhibiting the binding of amyloid beta peptides to alpha-7nicotinic acetylcholine receptors. Another object of the invention is toprovide a predictive method, a method for diagnosis, a method to monitorprognosis, a method to monitor the progression, and a method to monitorthe therapeutic efficacy for any therapeutic intervention used inAlzheimer's disease. Still another object of the invention is to providea method for identifying compounds which inhibit the binding of Aβpeptides with α7 nAChRs, either by binding to Aβ peptides or to α7nAChRs.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to a method of treating aneurodegenerative disorder in a subject (preferably, a human) in needthereof which comprises administering to the subject an amount of acompound effective to inhibit the binding of an amyloid beta peptide,preferably Aβ₁₋₄₂, to alpha-7 nAChRs, preferably, human alpha-7 nAChRs.Since alpha-8 and alpha-9 nAChRs are similar with respect to structureand function to alpha-7 nAChRs, it is possible that blocking theinteraction of β-amyloid with alpha-8 and alpha-9 nAChRs would havetherapeutic benefit as well.

[0009] Neurodegenerative disorders included within the methods of thepresent invention include, but are not limited to, Alzheimer's disease,Pick's disease, diffuse Lewy body disease, progressive supranuclearpalsy (Steel-Richardson syndrome), multisystem degeneration (Shy-Dragersyndrome), motor neuron diseases including amyotrophic lateralsclerosis, degenerative ataxias, cortical basal degeneration,ALS-Parkinson's-Dementia complex of Guam, subacute sclerosingpanencephalitis, Huntington's disease, Parkinson's disease,synucleinopathies, primary progressive aphasia, striatonigraldegeneration, Machado-Joseph disease/spinocerebellar ataxia type 3 andolivopontocerebellar degenerations, Gilles De La Tourette's disease,bulbar and pseudobulbar palsy, spinal and spinobulbar muscular atrophy(Kennedy's disease), primary lateral sclerosis, familial spasticparaplegia, Werdnig-Hoffmann disease, Kugelberg-Welander disease,Tay-Sach's disease, Sandhoff disease, familial spastic disease,Wohlfart-Kugelberg-Welander disease, spastic paraparesis, progressivemultifocal leukoencephalopathy, and prion diseases (includingCreutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker disease, Kuru andfatal familial insomnia).

[0010] Other conditions also included within the methods of the presentinvention include age-related dementia and other dementias andconditions with memory loss including vascular dementia, diffuse whitematter disease (Binswanger's disease), dementia of endocrine ormetabolic origin, dementia of head trauma and diffuse brain damage,dementia pugilistica and frontal lobe dementia. Also otherneurodegenerative disorders resulting from cerebral ischemia orinfaction including embolic occlusion and thrombotic occlusion as wellas intracranial hemorrhage of any type (including, but not limited to,epidural, subdural, subarachnoid and intracerebral), and intracranialand intravertebral lesions (including, but not limited to, contusion,penetration, shear, compression and laceration).

[0011] Preferably, the neurodegenerative disorder is selected fromAlzheimer's disease, Parkinson's disease, Tourette's syndrome,amyotrophic lateral sclerosis, age-related memory loss, senility andage-related dementia, most preferably, the neurodegenerative disorder isAlzheimer's disease. Because, most preferably, the neurodegenerativedisorder is Alzheimer's disease, also defined as an amyloidosis, otherconditions within the methods of the present invention include otheramyloidosis which share features including, but not limited to,hereditary cerebral angiopathy, nonneuropathic hereditary amyloid,Down's syndrome, macroglobulinemia, secondary familial Mediterraneanfever, Muckle-Wells syndrome, multiple myeloma, pancreatic- andcardiac-related amyloidosis, chronic hemodialysis arthropathy, andFinnish and Iowa amyloidosis.

[0012] In one embodiment of the invention is a method of treating and/orpreventing dementia in an Alzheimer's patient (as well as a method fortreating and/or preventing other clinical manifestations of Alzheimer'sdisease that include, but are not limited to, cognitive and languagedeficits, apraxias, depression, delusions and other neuropsychiatricsymptoms and signs, and movement and gait abnormalities) which comprisesadministering to the subject a therapeutically effective amount of acompound to inhibit the binding of an amyloid beta peptide (preferably,Aβ₁₋₄₂)with nAChRs, preferable alpha-7 nAChRs, most preferably, humanalpha-7 nAChRs.

[0013] In a second embodiment of the invention is a method of improvingmemory and/or mental status and/or of halting the progression of mentaldeterioration in an Alzheimer's disease patient which comprisesadministering to the subject a therapeutically effective amount of acompound to inhibit the binding of an amyloid beta peptide (preferably,Aβ₁₋₄₂) with nAChRs, preferably alpha-7 nAChRs, most preferably, humanalpha-7 nAChRs.

[0014] Preferably, the compound used in the methods of treatingneurodegenerative disorders, treating and/or preventing Alzheimer'sdisease, and improving memory and/or halting the progression of mentaldeterioration in an Alzheimer's disease patient is not estrogen,raloxifene, droloxifene, tamoxifen, idoxifene or levomeloxifene; morepreferably, the compound is not estrogen or a selective estrogenreceptor modulator (SERM). A SERM is an estrogen receptor ligand thatexhibits estrogen agonist activity in the cardiovascular system, CNS andbone, and estrogen antagonist activity in reproductive tissues, such asbreast and uterus.

[0015] Also included in the invention is the use of a compound whichinhibits the binding of an amyloid beta peptide (preferably Aβ₁₋₄₂ ) toan alpha-7 nAChR (preferably, a human alpha-7 nAChR) in the preparationof a medicament for the treatment of a neurodegenerative disorder in asubject (preferably, a human) in need thereof.

[0016] Another illustration of the invention is the use of a compoundwhich inhibits the binding of an amyloid beta peptide (preferablyAβ₁₋₄₂) to alpha-7 nAChRs (preferably, human alpha-7 nAChRs) in thepreparation of a medicament for: a) improving memory, b) halting theprogression of the mental deterioration seen in Alzheimer's diseasepatients, c) treating dementia, d) preventing dementia in an Alzheimer'spatient, and e) treating and/or preventing other clinical manifestationsof Alzheimer's disease that include, but are not limited to, cognitiveand language deficits, apraxias, depression, delusions and otherneuropsychiatric symptoms and signs, and movement and gait abnormalitiesin an Alzheimer's patient.

[0017] In another aspect of the invention is a compound of the formulaI:

[0018] wherein

[0019] R₁ is hydrogen or C₁-C₄ alkyl;

[0020] R₂ is selected from hydrogen, C₁-C₆ alkyl, aryl or C₇-C₁₀aralkyl;

[0021] R₃ is selected from hydrogen, C₁-C₆ alkyl, C₃-C₁₀ alkenyl, C₃-C₈cycloalkylC₁-C₆ alkyl, C₁-C₆ alkoxycarbonylC₁-C₆ alkyl, C₁-C₆ alkylthio,heteroarylC₁-C₄ alkyl, unsubstituted or substituted aryl orunsubstituted or substituted C₇-C₁₀ aralkyl wherein the substituent onthe aryl or aralkyl are one or more substituents independently selectedfrom the group consisting of halogen, hydroxy, C₁-C₆ alkyl andunsubstituted or substituted C₁-C₆ alkoxy wherein the substituents onthe alkoxy are one or more substituents independently selected fromamino, C₁-C₆ alkylamino, C₁-C₆ dialkylamino, pyrrolidinyl, piperidinyl,azepinyl or morpholinyl; or

[0022] R₂ and R₃, together with the nitrogen to which they are attached,form a five or six-membered heterocyclic ring selected frompyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl or piperazinyl;

[0023] R₄ is C₁-C₆ alkyl, aryl, or C₇-C₁₀ aralkyl; and

[0024] R₅ and R₆ are each independently selected from hydrogen, C₁-C₆alkyl, C₃-C₁₀alkenyl, C₁-C₈ alkylcarbonyl, or diphenylphosphinyl;

[0025] and pharmaceutically acceptable salts and prodrugs thereof.

[0026] In preferred compounds of formula I,

[0027] R₁ is hydrogen;

[0028] R₂ is selected from hydrogen or C₁-C₄ alkyl;

[0029] R₃ is selected from C₁-C₄ alkyl, C₃-C₁₀ alkenyl, C₅-C₆cycloalkylC₁-C4 ₆ alkyl, C₁-C₆ alkoxycarbonylC₁-C₄ alkyl, C₁-C₆alkylthio, heteroarylC₁-C₄ alkyl, or unsubstituted or substituted C₇-C₁₀aralkyl wherein the substituent on the aralkyl are one or twosubstituents independently selected from the group consisting ofhalogen, hydroxy, C₁-C₄ alkyl and unsubstituted or substituted C₁-C₄alkoxy wherein the substituents on the alkoxy are one or twosubstituents independently selected from amino, C₁-C₄ alkylamino, C₁-C₄dialkylamino, pyrrolidinyl, or piperidinyl; or

[0030] R₂ and R₃, together with the nitrogen to which they are attached,form a morpholinyl ring;

[0031] R₄ is C₁-C₄ alkyl; and

[0032] R₅ and R₆ are each independently selected from hydrogen, C₁-C₄alkyl, C₃-C₆ alkenyl, C₁-C₆ alkylcarbonyl, or diphenylphosphinyl.

[0033] In a subclass of compounds of formula I are compounds having theformula

[0034] wherein

[0035] R₁ is hydrogen or C₁-C₄ alkyl;

[0036] R₂ and R₃ are each independently selected from hydrogen, C₁-C₆alkyl, aryl or C₇-C₁₀ aralkyl; and

[0037] R₄ is C₁-C₆ alkyl, aryl, or C₇-C₁₀ aralkyl; and pharmaceuticallyacceptable salts thereof.

[0038] Compounds of formula I are novel compounds which block theinteraction of beta-amyloid with alpha-7 nAChRs. More specifically, thecompounds of formula I inhibit the binding of Aβ₁₋₄₂ with human alpha-7nAChRs by binding to Aβ₁₋₄₂. The orientation between the nitrogen atomand R₄ on the appropriate ring can be either cis or trans. Preferably,the compound is5,8-dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene,and pharmaceutically acceptable salts thereof.

[0039] Other compounds useful in the methods of the present inventioninhibit the binding of Aβ₁₋₄₂ with human alpha-7 nAChRs by binding tohuman alpha-7 nAChRs directly. An example of such a compound which bindsto human alpha-7 nAChRs is α-bungarotoxin.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention provides methods of treatingneurodegenerative disorders by inhibiting the binding of amyloid betapeptides to alpha-7 nAChRs. Neurodegenerative disorders included withinthe methods of the present invention include, but are not limited to,Alzheimer's disease, Pick's disease, diffuse Lewy body disease,progressive supranuclear palsy (Steel-Richardson syndrome), multisystemdegeneration (Shy-Drager syndrome), motor neuron diseases includingamyotrophic lateral sclerosis, degenerative ataxias, cortical basaldegeneration, ALS-Parkinson's-Dementia complex of Guam, subacutesclerosing panencephalitis, Huntington's disease, Parkinson's disease,synucleinopathies, primary progressive aphasia, striatonigraldegeneration, Machado-Joseph disease/spinocerebellar ataxia type 3 andolivopontocerebellar degenerations, Gilles De La Tourette's disease,bulbar and pseudobulbar palsy, spinal and spinobulbar muscular atrophy(Kennedy's disease), primary lateral sclerosis, familial spasticparaplegia, Werdnig-Hoffmann disease, Kugelberg-Welander disease,Tay-Sach's disease, Sandhoff disease, familial spastic disease,Wohlfart-Kugelberg-Welander disease, spastic paraparesis, progressivemultifocal leukoencephalopathy, and prion diseases (includingCreutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker disease, Kuru andfatal familial insomnia).

[0041] Other conditions also included within the methods of the presentinvention include age-related dementia and other dementias andconditions with memory loss including vascular dementia, diffuse whitematter disease (Binswanger's disease), dementia of endocrine ormetabolic origin, dementia of head trauma and diffuse brain damage,dementia pugilistica and frontal lobe dementia. Also otherneurodegenerative disorders resulting from cerebral ischemia orinfaction including embolic occlusion and thrombotic occlusion as wellas intracranial hemorrhage of any type (including, but not limited to,epidural, subdural, subarachnoid and intracerebral), and intracranialand intravertebral lesions (including, but not limited to, contusion,penetration, shear, compression and laceration).

[0042] Preferably, the neurodegenerative disorder is selected fromAlzheimer's disease, Parkinson's disease, Tourette's syndrome,amyotrophic lateral sclerosis, age-related memory loss, senility andage-related dementia, most preferably, the neurodegenerative disorder isAlzheimer's disease. Because, most preferably, the neurodegenerativedisorder is Alzheimer's disease, also defined as an amyloidosis, otherconditions within the methods of the present invention include otheramyloidosis which share features including, but not limited to,hereditary cerebral angiopathy, nonneuropathic hereditary amyloid,Down's syndrome, macroglobulinemia, secondary familial Mediterraneanfever, Muckle-Wells syndrome, multiple myeloma, pancreatic- andcardiac-related amyloidosis, chronic hemodialysis arthropathy, andFinnish and Iowa amyloidosis.

[0043] The terms “amyloid beta”, “amyloid beta peptide” or“beta-amyloid” as used herein, refer to amyloid beta peptides andinclude the Aβ₁₋₄₀, Aβ₁₋₄₂ and Aβ₁₋₄₃ peptides and their fragments.Examples of fragments of amyloid beta peptides that have been shown tohave biological activity and are useful in the methods of the presentinvention include, but not limited to, fragment 1-28, and fragment 25-35(e.g., Yatin S M, Aksenov M, Butterfield D A. Neurochem Res March1999;24 (3):427-35; Hirakura Y, Satoh Y, Hirashima N, Suzuki T, Kagan BL, Kirino Y. Biochem Mol Biol Int November 1998;46(4):787-94; MazziottiM, Perlmutter D H. Biochem J Jun. 1, 1998;332 Pt 2):517-24; Perovic S,Bohm M, Meesters E, Meinhardt A, Pergande G, Muller W E. Mech Ageing DevMar. 16, 1998;101(1-2):1-19; Muller W E, Eckert G P, Scheuer K, Cairns NJ, Maras A, Gattaz W F. Amyloid March 1998;5(1):10-5; Butterfield D A,Martin L, Carney J M, Hensley K. Life Sci 1996;58(3):217-28; Forloni G,Lucca E, Angeretti N, Della Torre P, Salmona M. J Neurochem November1997; 69(5):2048-54; Heese K, Hock C, Otten U. J Neurochem February1998;70(2):699-707; Blanchard B J, Konopka G, Russell M, Ingram V M.Brain Res Nov. 21, 1997; 776(1-2):40-50; Wu A, Derrico C A, Hatem L,Colvin R A. Neuroscience October 1997;80(3):675-84; Muller W E, Romero FJ, Perovic S, Pergande G, Pialoglou P. J Neurochem June1997;68(6):2371-7; Suh Y H. J Neurochem May 1997; 68(5):1781-91;Parpura-Gill A, Beitz D, Uemura E. Brain Res Apr. 18,1997;754(1-2):65-71; Fletcher T G, Keire D A. Protein Sci March1997;6(3):666-75; Scorziello A, Meucci O, Calvani M, Schettini G.Neurochem Res March 1997;22(3):257-65); Miguel-Hidalgo J J, Vecino B,Fernandez-Novoa L, Alvarez A, Cacabelos R. Eur NeuropsychopharmacolAugust 1998;8(3):203-8; Maneiro E, Lombardi V R, Lagares R, Cacabelos R.Methods Find Exp Clin Pharmacol January-February 1997;19(1):5-12).

[0044] The term “subject” as used herein, refers to an animal,preferably a mammal, most preferably a human, who has been the object oftreatment, observation or experiment.

[0045] The term “therapeutically effective amount” as used herein, meansthat amount of active compound or pharmaceutical agent that elicits thebiological or medicinal response in a tissue system, animal or humanthat is being sought by a researcher, veterinarian, medical doctor orother clinician, which includes alleviation of the symptoms of thedisease or disorder being treated.

[0046] The term “alkyl” shall mean straight or branched chain alkanes ofone to ten carbon atoms, or any number within this range. For example,alkyl radicals include, methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, t-butyl, n-pentyl, 3-(2-methyl)butyl, 2-pentyl,2-methylbutyl, neopentyl, n-hexyl, 2-hexyl and 2-methylpentyl. Alkoxyradicals are oxygen ethers formed from the previously described straightor branched chain alkyl groups. Cycloalkyl groups contain 3 to 8 ringcarbons and preferably 5 to 7 carbons. Similarly, alkenyl and alkynylgroups include straight and branched chain alkenes and alkynes having 2to 10 carbon atoms, or any number within this range.

[0047] The term “aryl” indicates aromatic groups such as phenyl andnaphthyl.

[0048] The term “C₇-C₁₀ aralkyl” means an alkyl group substituted withan aryl group wherein the total number of carbon atoms is between 7 and10 (e.g., benzyl, phenylethyl, phenylpropyl).

[0049] The term “heteroaryl” as used herein represents an unsubstitutedor substituted stable five or six membered monocyclic aromatic ringsystem or an unsubstituted or substituted nine or ten memberedbenzo-fused heteroaromatic ring system or bicyclic heteroaromatic ringsystem which consists of carbon atoms and from one to four heteroatomsselected from N, O or S, and wherein the nitrogen or sulfur heteroatomsmay optionally be oxidized, and the nitrogen heteroatom may optionallybe quaternized. The heteroaryl group may be attached at any heteroatomor carbon atom that results in the creation of a stable structure.Examples of heteroaryl groups include, but are not limited to pyridyl,pyridazinyl, thienyl, furanyl, imidazolyl, isoxazolyl, oxazolyl,pyrazolyl, pyrrolyl, thiazolyl, thiadiazolyl, triazolyl, benzimidazolyl,benzofuranyl, benzothienyl, benzisoxazolyl, benzoxazolyl,benzopyrazolyl, indolyl, benzothiazolyl, benzothiadiazolyl,benzotriazolyl adeninyl or quinolinyl. Prefered heteroaryl groupsinclude pyridyl, pyrrolyl, pyrazinyl, thiadiazolyl, pyrazolyl, thienyl,triazolyl and quinolinyl.

[0050] The term “N(CH₂)₅” means a piperidinyl group.

[0051] The term “cC₆H₁₁” refers to a cyclohexyl group.

[0052] When a particular group is “substituted” (e.g., aryl, aralkyl),that group may have one or more substituents, preferably from one tofive substituents, more preferably from one to three substituents, mostpreferably from one to two substituents, independently selected from thelist of substituents.

[0053] Under standard nomenclature used throughout this disclosure, theterminal portion of the designated side chain is described first,followed by the adjacent functionality toward the point of attachment.Thus, for example, a “phenylC₁-C₆ alkylamidoC₁-C₆alkyl” substituentrefers to a group of the formula

[0054] Compounds which are useful in the methods of the presentinvention for inhibiting the interaction of Aβ₁₋₄₀ and Aβ₁₋₄₂ to thealpha-7 subtype of nAChRs for either the purpose of direct therapeuticintervention or in order to screen for compounds which act via thismechanism include compounds of formula I, especially5,8-dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(Compound 9), (−)-nicotine, (rac)-epibatidine, α-bungarotoxin, andpharmaceutically acceptable salts thereof.

[0055] Certain peptide stretches of the human alpha-7 nAChR bind toamyloid beta and can be used in place of the alpha-7 nAChR together withamyloid beta for the purpose of screening libraries to find compoundswhich block the interaction of amyloid beta and the human alpha-7 nAChR.Included among these peptide stretches of the human alpha-7 nAChR arealpha-7 nAChR193-224 and smaller peptides derived thereof as listed inthe Table. TABLE Amelioration of the Aβ₁₋₄₂ Meditated Inhibition of AChCompound Release of Rat Cortical Synaptosomes (%) human alpha-7 81% at10 μM nAChR193-224 79% at 1 μM Ac-NGEWDLVGIPGKRSERFYECCKEPYPDVTFTV-NH2human alpha-7 79% at 10 μM nAChR200-214 71% at 1 μMAc-GIPGKRSERFYECCK-NH2 human alpha-7 81% at 10 μM nAChR206-216 77% at 1μM Ac-SERFYECCKEP-NH2 human alpha-7 84% at 10 μM nAChR206-216 82% at 1μM oxidized (cyclic) CC: Ac-SERFYECCKEP-NH2 human alpha-7 22% at 10 μMnAChR206-216 10% at 1 μM SERFYECCKEP human alpha-7 72% at 10 μMnAChR210-213 59% at 1 μM Ac-YECC-NH2

[0056] The standard one-letter code for the amino acids has beenemployed for the compounds. This code is listed in Lehninger, A. I.“Biochemistry” Second Edition, Worth Publishers, Inc., New York, 1976, p73-75.

[0057] For use in medicine, the salts of the compounds of this inventionrefer to non-toxic “pharmaceutically acceptable salts.” Other salts may,however, be useful in the preparation of compounds according to thisinvention or of their pharmaceutically acceptable salts. Suitablepharmaceutically acceptable salts of the compounds of this inventioninclude acid addition salts which may, for example, be formed by mixinga solution of the compound with a solution of a pharmaceuticallyacceptable acid such as hydrochloric acid, sulfuric acid, fumaric acid,maleic acid, succinic acid, acetic acid, benzoic acid, citric acid,tartaric acid, carbonic acid or phosphoric acid. Furthermore, where thecompounds of the invention carry an acidic moiety, suitablepharmaceutically acceptable salts thereof may include alkali metalsalts, e.g., sodium or potassium salts; alkaline earth metal salts,e.g., calcium or magnesium salts; and salts formed with suitable organicligands, e.g., quaternary ammonium salts.

[0058] The present invention includes within its scope prodrugs of thecompounds of this invention. A prodrug is inactive as administered, butbecomes activated in vivo. The prodrug is converted to the parent drugchemically or by specific enzyme(s). Higuchi, T.; Stella, V., Eds.“Pro-Drugs as Novel Drug Delivery Systems”; American Chemical Society:Washington, DC, 1976. In general, such prodrugs will be functionalderivatives of the compounds which are readily convertible in vivo intothe required compound. Thus, in the methods of treatment of the presentinvention, the term “administering” shall encompass the treatment of thevarious disorders described with the compound specifically disclosed orwith a compound which may not be specifically disclosed, but whichconverts to the specified compound in vivo after administration to thepatient. Conventional procedures for the selection and preparation ofsuitable prodrug derivatives are described, for example, in “Design ofProdrugs”, ed. H. Bundgaard, Elsevier, 1985.

[0059] Where the compounds according to this invention have at least onechiral center, they may accordingly exist as enantiomers. Where thecompounds possess two or more chiral centers, they may additionallyexist as diastereomers. It is to be understood that all such isomers andmixtures thereof are encompassed within the scope of the presentinvention. Furthermore, some of the crystalline forms for the compoundsmay exist as polymorphs and as such are intended to be included in thepresent invention. In addition, some of the compounds may form solvateswith water (i.e., hydrates) or common organic solvents, and suchsolvates are also intended to be encompassed within the scope of thisinvention.

[0060] (−)-Nicotine is (−)-1-methyl-2-(3-pyridinyl)pyrrolidine and isreadily available from Sigma Chemical Company.

[0061] (+/−)-Epibatidine isexo-(+/−)-2-(6-chloro-3-pyridinyl)-7-azabicyclo[2.2.1]heptane and isreadily available from Sigma Chemical Company.

[0062] α-Bungarotoxin is a 74 amino acid peptide which is commerciallyavailable from Research Biochemicals Inc. α-Bungarotoxin and its aminoacid sequence are described in Lee, C. Y. Annu. Rev. Pharmacol. 1972,12, 265-281.

[0063]¹²⁵I-Aβ₁₋₄₀, fluo-Aβ₁₋₄₀, and anti-alpha-7 nAChR antibodies arecommercially available Amersham Pharmacia Biotech, Advanced Bioconceptsand Research Biochemicals International, respectively.

[0064]¹²⁵I-α-bungarotoxin is commercially available from AmershamPharmacia Biotech.

[0065] The present invention therefore provides a method of treating aneurodegenerative disorder, which comprises administering any of thecompounds as defined herein in a quantity effective to treat theneurodegenerative disorder. Preferably, the compound is not estrogen,raloxifene, droloxifene, tamoxifen, idoxifene or levomeloxifene; morepreferably, the compound is not estrogen or a selective estrogenreceptor modulator (SERM). The compound may be administered to a patientafflicted with a neurodegenerative disorder by any conventional route ofadministration, including, but not limited to, intravenous, oral,subcutaneous, intramuscular, intradermal, buccal, intracerebral andother parenteral routes. The quantity of the compound which is effectivefor treating a neurodegenerative disorder is between 0.01 mg per kg and10 mg per kg of subject body weight.

[0066] The method of treating neurodegenerative disorders described inthe present invention may also be carried out using a pharmaceuticalcomposition comprising any of the compounds as defined herein and apharmaceutically acceptable carrier. The pharmaceutical composition maycontain between about 0.5 mg and 200 mg of the compound, and may beconstituted into any form suitable for the mode of administrationselected. Carriers include necessary and inert pharmaceuticalexcipients, including, but not limited to, binders, suspending agents,lubricants, flavorants, sweeteners, preservatives, dyes, and coatings.Compositions suitable for oral administration include solid forms, suchas pills, capsules, granules, tablets, caplets, and powders, and liquidforms, such as solutions, syrups, elixers, and suspensions. Forms usefulfor intracerebral and other parenteral routes of administration includesterile solutions, emulsions and suspensions.

[0067] Optimal dosages to be administered may be readily determined bythose skilled in the art, and will vary with the particular compoundused, the mode of administration, the strength of the preparation, themode of administration, and the advancement of the disease condition. Inaddition, factors associated with the particular patient being treated,including patient age, body weight, diet, physical activity and time ofadministration, and associated co-morbidities and clinical conditionswill result in the need to adjust dosages.

[0068] The present invention also provides diagnostic tools useful fordiagnosing Alzheimer's disease. Alzheimer's disease (AD) exhibitsneuropathological abnormalities in the olfactory system located in thenasal cavity. These include the presence of dystrophic neurites thatexhibit immunoreactivity for tau, neurofilaments, apolipoprotein E andother proteins, abnormal tau protein, increase in superoxide dismutase,and beta-amyloid deposition in the primary sensory (olfactory receptor)cells and nerve fibres of the nasal mucosa tissue (Arnold et al., Ann NY Acad Sci Nov. 30, 1998;855:762-75; Hock et al., Eur Neurol July1998;40(1):31-6; Johnson et al., Neurobiol Aging November-December1994;15(6):675-80; Kulkarni-Narla et al., Exp Neurol August1996;140(2):115-25; Lee et al., Exp Neurol May 1993;121(1):93-105;Tabaton et al., Neurology March 1991;41(3):391-4; Talamo et al., Ann N YAcad Sci 1991;640:1-7; Yamagishi et al., Ann Otol Rhinol Laryngol May1998;107(5 Pt 1):421-6; Yamagishi et al., Nippon Jibiinkoka Gakkai KaihoJanuary 1994;97(1):51-60). These observations recapitulate theneuropathological profile and neurodegenerative abnormalities (e.g.,cytoskeletal changes, protein immunoreactivity and beta-amyloiddeposition) observed in central nervous system neurons from AD patients.Routine access to these sensory neurons and fibers can be done withnasal biopsy in AD patients (e.g., Feron et al., Arch Otolaryngol HeadNeck Surg August 1998;124(8):861-6).

[0069] Olfactory neuroblasts (olfactory neurons obtained by biopsy andplaced in primary cell culture) from AD patients produce carboxyterminal amyloid precursor protein (APP) fragments that containbeta-amyloid (A-beta) (Crino et al., Ann Otol Rhinol Laryngol August1995;104(8):655-61). Crino et al. showed labeling of A-beta in the basalthird of the olfactory neuroepithelium and in axons projecting throughthe lamina propria of AD patients. Thioflavin-S staining that detectsamyloid deposition was also observed in the basal third of the olfactoryneuroepithelium from AD patients. Alpha 7 nicotinic acetylcholinereceptors are present in olfactory neurons probably including olfactoryreceptor cells in the nasal cavity (Alkondon et al., Neurosci Lett Aug.1, 1994;176(2):152-6; Alkondon et al., Eur J Neurosci December1997;9(12):2734-42; Bouvet et al., Neurosci Res February1988;5(3):214-23; Edwards et al., Experientia Aug. 15,1987;43(8):868-73; Edwards et al., Experientia Mar. 15,1988;44(3):208-11; Seguela et al., J Neurosci February1993;13(2):596-604).

[0070] Beta-amyloid peptide increases cytosolic-free Ca²⁺ in ADlymphoblasts (Ibarreta et al., Alzheimer Dis Assoc Disord December1997;11(4):220-7), and elevates mitogen-induced Ca²⁺ responses infreshly prepared human lymphocytes (Eckert et al., Life Sci1994;55(25-26):2019-29). Amyloid precursor protein (APP) can be inducedon the cell surface of human lymphocytes upon stimulation (Bullido etal., Biochim Biophys Acta Aug. 21, 1996;1313(1):54-62) and increasedAPP-770 isoform occurs in lymphocytes from AD patients (Ebstein et al.,Brain Res Mol Brain Res January 1996;35(1-2):260-8). Lymphoblastoidcells from patients with early-onset and late-onset familial AD showincreased expression of beta-APP mRNA and protein (Matsumoto et al., EurJ Biochem Oct. 1, 1993;217(1):21-7). Lymphocytes from AD patients alsoexhibit an increased mRNA level for alpha 7 nicotinic receptor(Hellstrom-Lindahl et al., Brain Res Mol Brain Res Mar. 20,1999;66(1-2):94-103)

[0071] Based on the information described above, we propose that theanalysis of the alpha 7 nicotinic acetylcholine receptor—beta amyloidpeptides interaction in circulating blood cells and olfactoryneuroepithelial neurons/neuronal processes or olfactory neuroblastsobtained from AD patients could be used as AD diagnostic tools, markersof AD progression and prognosis, and markers of therapeutic efficacy forany intervention or treatment targeting AD.

[0072] Thus, the present invention provides methods for diagnosingAlzheimer's disease, monitoring the progression and prognosis ofAlzheimer's disease and/or monitoring the therapeutic efficacy of anyintervention or treatment of Alzheimer's disease comprising:

[0073] (a) obtaining a test sample from a subject wherein the testsample comprises circulating blood cells and/or olfactoryneuroepithelial neuronal cell bodies or their neuronal processes (i.e.,dendrites and axon of a nueron); and

[0074] (b) analyzing the test sample for interaction of an amyloid betapeptide (including, but not limited to, Aβ₁₋₄₀, Aβ₁₋₄₂ and Aβ₁₋₄₃peptides and their fragments) with alpha-7 nicotinic acetylcholinereceptors.

[0075] The compounds of formula I, such as5,8-Dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(Compound 9), are made according to the procedures described in theSchemes and Examples which follow.

[0076] Abbreviations used in the instant specification, particularly theSchemes and Examples, are as follows: Ac = acetyl Ach = acetylcholineAcOH = acetic acid BSA = bovine serum albumin DMF = N,N-dimethylformamide DMSO = dimethyl sulfoxide Et₃N = triethyl amine EtOAc = ethylacetate FCS = fetal calf serum i-Pr = isopropyl Me = methyl MeI = methyliodide nAChR = nicotinic acetylcholine receptor Ph = phenyl PCC =pyridinium chlorochromate TEA = triethyl amine THF = tetrahydrofuran TLC= thin layer chromatography

[0077]

[0078] Compounds of the invention can be prepared as shown in Scheme 1.First a Diels-Alder reaction is performed on benzophenone (1) with asuitable diene such as isoprene to give a dione such as (2). Then,base-catalyzed isomerization of (2) affords a 1,4-dihydroxyphenylcompound (3), which is converted to dimethyl ether (4). Hydroborationfollowed by oxidation give alcohol (5), which is then oxidized to giveketone (6). Reductive amination with an amine such as propyl amine isthen carried out using a suitable hydride reducing agent such as sodiumcyanoborohydride, to give, for example, compound 7. This material canthen be subjected to a reductive amination reaction such as withpropionaldehyde as shown to yield (8). Compound (8) is then treated withHBr in acetic acid to cleave the methyl ethers and form dihydroxycompound (9). Alternatively, BBr₃ may be used to cleave the methylethers and form dihydroxy compound (9). Moreover, a deficiency of BBr₃may be used to provide compounds in which only one of the methyl ethershas been removed to afford compounds with one hydroxy and one methoxygroup.

[0079] A further means of preparing compounds of the present inventionis illustrated in Scheme 2. A suitable propargyl alcohol, such as3-hydroxy-3-methyl-1-butyne (10, R₄=Me) is dehydrated to give an enynesuch as compound 11. This material is then subjected to anaminomercuration reaction to afford a 2-amino-1,4-butadiene such ascompound (12). Diels-Alder reaction of compound (12) with benzophenone(1) gives (13) which can be isomerized as in Scheme 1 with base to givethe 1,5-dihyroxy compound (14). Reduction of the double bond of (14)catalytically with hydrogen and palladium on carbon, such as 10%palladium on carbon, yields compounds of the invention such as (15).

[0080] Compounds of type 9 can be treated with a base such astriethylamine in a suitable solvent such as dioxane or methylenechloride along with electrophiles such as acid halides, phosphinylhalides, or alkyl halides to give the products of substitution on one orboth of the phenolic hydroxyls. Such compounds can be active bythemselves, or serve as prodrugs for compound 9.

[0081] The following Examples are set forth to aid in the understandingof the invention, and are not intended and should not be construed tolimit in any way the invention set forth in the claims which followthereafter.

EXAMPLE 1 Preparation of5,8-Dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(9) a. 5,8-Dihydroxy-2-methyl-1,4-dihydronaphthalene (3)

[0082] To a solution of p-benzoquinone (10.00 g, 92.5 mmol) in 1Msolution of lithium perchlorate, in nitromethane (300 mL) was addedisoprene (9.24 mL, 92.3 mmol) at room temperature. The resultantreaction mixture was stirred at room temperature under N₂ for 4 hours.The reaction mixture was partitioned between EtOAc (500 mL) and water(200 mL). The organic layer was washed with brine, dried over sodiumsulfate and concentrated to give 2 as brown solid. The reaction wasrepeated on 15 g of benzoquinone to afford additional 2. These two runswere combined and carried on without further purification. To a solutionof 2 (35.00 g, 199 mmol) in methylene chloride (400 mL) was addedtriethylamine (40 mL). The reaction mixture was stirred at roomtemperature for 1 hr. The product was precipitated out of solution bythe addition of hexane (300 mL). The solid was collected by filtrationand dried in a dessicator under high vaccuum overnight to provide 3 as alight brown solid.

[0083]¹H NMR (300 MHz, DMSO-d₆): δ1.75 (s, 3H), 3.00-3.01 (m, 2H), 3.09(s, 2H), 5.53 (s, 1H), 6.43 (s, 2H), 8.49-8.52 (m, 2H).

b. 5,8-Dimethoxy-2-methyl-1,4-dihydronaphthalene (4)

[0084] To a cold (−78° C.) solution of hydroquinone 3 (17.00 g, 96.6mmol) in DMF under N₂ was added unwashed 60% sodium hydride in mineraloil (8.90 g, 222.5 mmol). The resultant reaction mixture was warmed toroom temperature over a 30 min period and subsequently treated withmethyl iodide (14.3 mL, 230 mmol). After stirring the reaction mixturefor 1 hr at room temperature the reaction mixture was diluted with ethylacetate (1.5 L) and washed with brine (3×500 ml). The organic solutionwas dried over sodium sulfate, filtered, concentrated, and the residuepurified on silica gel (elution with 20% ethyl acetatehexane) to afford4 as a light yellow oil which solidified upon standing.

[0085]¹H NMR (300 MHz, CD₃OD): δ1.77 (s, CH₃), 3.07-3.09 (m, 2H), 3.16(br s, 2H), 3.73(s, 3H), 3.75 (s, 3H), 5.52-5.53 (m, 1H), 6.65 (s, 2H).

c. 5,8-Dimethoxy-trans-2-hydroxy-3-methyl-1,2,3,4-tetrahydronaphthalene(5)

[0086] A solution of 4 (5.00 g, 24.5 mmol) in tetrahydrofuran (100 ml)was cooled to 0° C. and treated with 1 M borane-tetrahydrofuran complex(24.5 mL, 24.5 mmol) and the resulting solution was stirred at roomtemperature for 4 h. Then, 12 mL of 3 N NaOH solution was added slowlyto the stirring reaction solution followed by the addition of 6 mL of30% aqueous hydrogen peroxide. After stirring for 30 min, the resultantmixture was diluted with 500 mL of ethyl acetate and washed by brine(2×100 mL). The organic layer was dried over sodium sulfate, filteredand concentrated, and the residue was purified on silica gel (30% ethylacetate/hexane) to give 5 as a white solid.

[0087]¹H NMR (300 MHz, CDCl₃): δ1.13 (d, 3H, J=6.51 Hz), 1.60 (d, 1H),1.75-1.90 (m, 1H), 2.26 (dd, 1H, J=10.0 Hz, 17.57 Hz), 2.48 (dd, 1H,J=8.93 Hz, 17.10 Hz), 2.96 (dd, 1H, J=5.31,17.7 Hz), 3.16 (dd, 1H,J=5.33, 5.35 Hz), 3.63-3.69 (m, 1H), 3.78 (s, 6H), 6.62 (s, 2H).

d. 5,8-Dimethoxy-3-methyl-2-tetralone (6)

[0088] A solution of alcohol 5 (10 g, 45 mmol) and dichloromethane (200mL) at −30° C. was treated dropwise with oxalyl chloride (4.92 g, 24 mL,0.275 mol). The reaction was stirred at −30° C. for 30 min, cooled to−60° C., and DMSO (6.4 mL) was added slowly over 15 min. The reactionwas stirred for one hour, cooled to −78° C. for 30 min, and then treateddropwise with triethylamine (40 mL). The reaction was warmed to roomtemperature and stirred for 1 hr, followed by the addition of water anddichloromethane with thorough mixing. The organic layer was separated,dried with MgSO₄, filtered and the solvent was evaporated to an oil.Purification of this material using flash chromatography (flash silica,70/30:hexane/EtOAc) afforded 6 as a white crystalline solid.

[0089]¹H NMR (300 MHz, CDCl₃) δ6.7 (q, 2 H), 3.78 (s, 3 H), 3.75 (s, 3H), 3.5 (dd, 2 H), 3.3 (m, 1 H), 2.55 (m, 2 H), 1.2 (d, 3 H).

e. 5,8-Dimethoxy-2-N-propylamino-3-methyl-1,2,3,4-tetrahydronaphthalene(7)

[0090] To a solution of 6 (0.15 g, 0.68 mmol) in acetonitrile (10 mL)was added sodium cyanoborohydride (0.085 g, 1.30 mmol), 0.05 ml ofacetic acid and N-propylamine (0.08 mL, 1.3 mmol). The resultingsolution was stirred at room temperature overnight and poured into 10 mLof 1N NaOH solution. The mixture was extracted with EtOAc, dried oversodium sulfate, concentrated, and the residue purified by preparativeTLC (elution with 30% ethyl acetate in hexane) to give amine 7 as acolorless oil.

[0091]¹H NMR (300 MHz, CD₃OD): δ0.85 (d, 3H, J=7.07 Hz), 0.93-0.97 (m,3H), 1.09 (t, 2H), 1.49-1.61 (m, 2H), 2.12-2.42 (m, 2H), 2.51-2.76 (m,4H), 2.82-3.08 (m, 2H), 3.73 (s, 3H), 3.74 (s, 3H), 6.65 (s, 2H).

f.5,8-Dimethoxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(8)

[0092] To a solution of 7 (0.11 g, 0.42 mmol) in acetonitrile (10 ml)was added sodium cyanoborohydride (0.05 gm, 0.6 mmol), 0.03 mL of aceticacid and propionaldehyde (0.045 mL, 0.60 mmol). The resulting solutionwas stirred at room temperature overnight and poured into 10 mL of 1NNaOH solution. The mixture was extracted with EtOAc, dried over sodiumsulfate, concentrated, and the residue was purified by preparative TLC(elution with 30% ethyl acetate in hexane) to give amine 8 as a lightyellow solid.

[0093]¹H NMR (300 MHz, CD₃OD): δ0.84 (d, 3H, J=6.94 Hz), 0.92 (t, 2H,J=7.30, 7.32 Hz), 1.27-1.59 (m, 4H), 2.33-2.42 (m, 2H), 2.54-3.02 (m,8H), 3.73 (s, 3H), 3.76 (s, 3H), 6.66 (s, 2H).

[0094] In a similar manner was prepared compounds 19, 21, 25, 27, 29,35, 37, 39, 41, 52, and 54.

[0095] In order to separate the enantiomers of 8, 2.859 g of 8 waspassed through a CHIRALPAK® AD™ chiral cellulose-based high pressureliquid chromatography column (8 cm×30 cm) at 25° C. usinghexane/isopropyl alcohol (99/1) as the eluant to give two fractions asoils. Fraction 1 (18) had a 98.6% enantiomeric excess (e.e.) andfraction 2 (17) had a 97.9% e.e. Fraction 1 (0.306 g, 1.0 mmol) andfumaric acid (0.141 g, 1.2 mmol) were dissolved in ethanol (2 mL) withheating. The ethanol was evaporated and the residue triturated withdiethyl ether affording the fumarate salt of 18 as a white solid.Similarly obtained from Fraction 2 (0.301 g, 1.0 mmol) and fumaric acid(0.141 g, 1.2 mmol) was the fumarate sale of 17.

g.5,8-Dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(9)

[0096] A mixture of 8 (1.4 g, 4.6 mmol) and 3.5 mL of 48% aqueous HBr inacetic acid (3.5 mL) was stirred at 100° C. under N₂ overnight. Thereaction mixture was then cooled to 0° C. and extracted with diethylether (20 mL). The organic solution was neutralized with aqueous NaHCO₃and separated. The aqueous layer was extracted with ether (20 mL) andthe combined ether solutions were dried over Na₂SO₄, filtered, andconcentrated to give 9.

[0097]¹H NMR (600 MHz, CDCl₃): δ0.86-0.92 (dt, 6H), 1.13 (d, 3H, J=6.42Hz), 1.42-1.50 (m, 4H), 1.88-1.93 (m, 1H), 2.23-2.28 (m, 1H), 2.39-2.52(m, 6H), 2.61-2.63 (m, 1H), 2.90 (dd, 1H, J=4.75, 16.28 Hz), 2.95 (dd,1H, J=5.05, 16.75 Hz), 4.84 (br s, 2H), 6.50 (dd, 2H, J=8.52 Hz). CI-MS:m/e MH⁺ 278 (40%).

[0098] In a similar manner 17 and 18 were converted to 15 and 16respectively. Additionally, demethylation of the appropriate dimethylethers by the procedure described here led to the preparation ofcompounds 20, 22, 26, 28, 30, 32, 34, 36, 40, 42, 53, and 55. In thecourse of the demethylation of 37, the butyl ether was also removed toobtain 38.

EXAMPLE 2 Preparation of5,8-Dihydroxy-cis-2-(1-morpholinyl)-3-methyl-1,2,3,4-tetrahydronaphthalene(24) a.5,8-Dimethoxy-cis-2-(1-morpholinyl)-3-methyl-1,2,3,4-tetrahydronaphthalene(23).

[0099] Ketone 6 (0.299 g, 1.36 mmol) was dissolved in toluene (1 mL)followed by the addition of morpholine (0.130 g, 0.13 mL, 1.5 mmol) andTi(i-PrO)₄ (0.611 g, 0.64 mL, 2.15 mmol). The reaction mixture wasstirred for 15 hrs at room temperature. Methanol (2 mL) was addedfollowed by portionwise addition of NaBH₄ (0.15 g, 3.9 mmol) over 1 hr.Dichloromethane and 1N NaOH were added with thorough mixing and theorganic layer was separated, dried with MgSO₄, filtered and evaporatedto an oil. Purification of this material using flash chromatography(flash silica, 75/25: hexane/EtOAc) afforded product 23.

[0100]¹H NMR (300 MHz, DMSO-d₆) δ6.6 (s, 2 H), 3.6 (d, 6 H), 3.5 (s, 4H), 3.2 (s, 4 H), 3.2 (s, 6 H), 2.8 (d, 1 H), 2.7 (d, 1 H), 2.3 (m, 2H), 2.05 (m, 2 H), 0.6 (d, 3 H).

b.5,8-Dihydroxy-cis-2-(1-morpholinyl)-3-methyl-1,2,3,4-tetrahydronaphthalene(24).

[0101] A solution of 23 (20 mg, 0.066 mmol) and dichloromethane (2 mL)at −78° C. was treated with a 1 M solution of BBr₃ in dichloromethane (1mL, 1 mmol.) and stirred for 1 hr at −78° C. After warming to roomtemperature, methanol (5 mL) was added and the solvents were evaporated.Methanol addition to the residue followed by evaporation was done twice.The residue was dissolved in acetonitrile (25 mL) and treated withtriethylamine (2 mL). After stirring for 2 hrs, water and ethyl acetatewere added with thorough mixing. The organic layer was separated, driedwith MgSO₄, filtered, and solvent evaporated to yield 24 as an oil.

[0102]¹H NMR (300 MHz, CD₃OD) δ6.7 (s, 2 H), 3.4 (m, 4 H), 3.3 (m, 1 H),2.6 (m, 5 H), 1.9 (m, 1 H), 1.5 (m, 2 H), 1.05 (d, 3 H), 0.9 (m, 3 H).

EXAMPLE 3 Preparation of 5,8-Dimethoxy-cis andtrans-2-(N-propyl-N-propargyl)amino-3-methyl-1,2,3,4-tetrahydronaphthalene(31 and 33)

[0103] Ketone 6 (1 g, 4.5 mmol) was dissolved in acetonitrile (75 mL)followed by the addition of acetic acid (0.54 mL, 9 mmol, 2 eq.) andpropargylamine (0.6 mL, 9 mmol, 2 eq.). The reaction mixture was stirredat room temperature for 1 hr. Sodium cyanoborohydride (0.6 g, 9 mmol, 2eq.) was added portionwise (3×) over 1.5 hrs (every 30 min), and thereaction mixture was stirred overnight at room temperature. Ethylacetate and 1 N NaOH were added with thorough mixing and the organiclayer was separated, dried with MgSO₄, filtered and evaporated to anoil. The product was purified with flash chromatography (50:50/ethylacetate:hexane) to yield an oil of 5,8-dimethoxy-cis andtrans-2-N-(propargyl)amino-3-methyl-1,2,3,4-tetrahydronaphthalene (1.2g, 100%). This material was dissolved in acetonitrile along withpropionaldehyde (0.65 g, 9 mmol, 2 eq.) and acetic acid (0.5 mL, 9 mmol)and stirring for 1 hr at room temperature. One hour later, sodiumcyanoborohydride (0.6 g, 9 mmol, 2 eq.) was added portionwise (3×) over1.5 hours (every 30 mins). The reaction was stirred overnight at roomtemperature. Ethyl acetate and 1 N NaOH were added to the reaction withthorough mixing and the organic layer was separated, dried with MgSO₄,filtered and evaporated to a mixture of products 31 and 33. Purificationof this material using flash chromatography (flash silica,80:20/hexane:ether) afforded product 31 and 33.

[0104] Compound ¹H NMR (300 MHz, CDCl₃) δ6.6 (s, 2 H), 3.8 (s, 6 H), 3.4(q, 2 H), 3.0 (dd, 2 H), 2.6 (m, 4 H), 2.2 (m, 2 H), 1.85 (m, 1 H), 1.5(m, 2 H), 1.1 (d, 3 H), 0.9 (t, 3 H). Compound 33: ¹H NMR (300 MHz,CDCl₃) δ6.6 (s, 2 H), 3.78 (s, 3 H), 3.75 (s, 3 H), 3.6 (q, 2 H), 3.05(dd, 1 H), 2.75 (m, 2 H), 2.61 (m, 3 H), 2.3 (m, 2 H), 2.1 (s, 1 H),1.55 (m, 2 H), 0.9 (t, 3 H), 0.8 (d, 3 H).

EXAMPLE 4 Preparation of5-[2-(3-Methyl)butenyl]-8-hydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(43); and5-Hydroxy-8-[2-(3methyl)butenyl]-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(44)

[0105] Diol 9 (0.3 g, 1.2 mmol) was dissolved in acetone (40 mL)followed by the addition of potassium carbonate (0.19 g) and1-bromo-3-methyl-2-butene (0.1 mL, 0.87 mmol). The reaction mixture wasstirred for 48 hrs at room temperature. Dichloromethane and water wereadded with thorough mixing and the organic layer was separated, driedwith MgSO_(4,) filtered and the solvent was evaporated to yield an oil.Purification of this material using flash chromatography (flash silica,70:30/hexane:ether) afforded products 43 and 44. The regiochemicalstructural assignment between the two of them is uncertain. Compound 43:¹H NMR (300 MHz, CDCl₃) δ6.5 (s, 2 H), 5.5 (t, 1 H), 4.4 (m, 2 H), 3.0(m, 2 H), 2.4 (m, 8 H), 1.8 (m, 1 H), 1.72 (s, 3 H), 1.65 (s, 3 H), 1.4(m, 4 H), 1.1 (dd, 3 H), 0.85 (t, 6 H).

[0106] Compound 44: ¹H NMR (300 MHz, CDCl₃) δ6.55 (s, 2 H), 5.45 (t, 1H), 4.4 (m, 2 H), 3.05 (dd, 1 H), 2.85 (dd, 1 H), 2.4 (m, 7 H), 1.65 (s,3 H), 1.6 (s, 3 H), 1.55 (m, 2 H), 1.4 (m, 4 H), 1.1 (m, 4 H), 1.1 (d, 3H), 0.9 (t, 6 H).

EXAMPLE 5 Preparation of5-Hydroxy-8-methoxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(45); and5-Methoxy-8-hydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(46)

[0107] Compound 8 (1.85 g, 6 mmol) was dissolved in dichloromethane (20mL) and cooled to −78° C., followed by the addition of boron tribromide(6 mL of a 1 M solution, 6 mmol, 1 eq.). The reaction mixture wasstirred at −78° C. for 1 hr and then warmed to room temperature for 2hrs. The reaction was quenched with methanol (5 mL), and the solvent wasevaporated (methanol quench repeated twice more). The resulting oil wasdried overnight under high vacuum (5 mm Hg). The residue was dissolvedin dichloromethane and NaHCO₃ was added, mixed thoroughly, and theorganic layer was separated, dried with MgSO₄, filtered and the solventevaporated to a mixture of two regioisomers 45 and 46 (1:1). Thepurification of a mixture (200 mg) was conducted on a reverse phase HPLC(C18 column, 69:30:1/water:acetonitrile:triflouroacetic acid) to afford45 and 46 as triflouroacetate salts. Compound 45 (TFA salt): ¹H NMR (300MHz, CDCl₃) δ6.65 (q, 2H), 4.7 (bs, 1 H), 3.7 (s, 3 H), 3.5 (m, 1 H),3.3 (m, 1H), 3.0 (m, 4H), 2.7 (m, 2 H), 2.3 (m, 1 H), 2.0 (m, 5 H), 1.15(d, 3 H), 0.9 (m, 6 H). Compound 46 (free base): ¹H NMR (300 MHz, CDCl₃)δ6.55 (q, 2 H), 4.3 (bs, 1 H), 3.75 (s, 3 H), 3.05 (dd, 1 H), 3.0 (dd, 1H), 2.6 (m, 1 H), 2.4 (m, 6 H), 2.2 (m, 1 H), 1.8 (m, 1 H), 1.4 (m, 4H), 1.1 (d, 3 H), 0.85 (t, 6 H). The regiochemistry of the structure of46 was confirmed through careful analysis of HMBC (HeteronuclearMultiple Bond Correlation) connectivities and nOe effects. The structureof 46 was established by connectivity between the methoxy substituent onthe aromatic ring and the benzylic methylene adjacent to themethyl-substituted carbon.

EXAMPLE 6 Preparation of 5,8-Dimethoxy-2-[N-(L-alanyl methylester)]-3-methyl-1,2,3,4-tetrahydronaphthalene (48)

[0108] Ketone 6 (1 g, 4.5 mmol) was dissolved in acetonitrile (75 mL)and acetic acid (0.54 mL, 9 mmol, 2 eq.), and alanine methyl esterhydrochloride (1.3 g, 9 mmol, 2 eq.) was added. The reaction was stirredat room temperature for 1 hr, and then sodium cyanoborohydride (0.6 g, 9mmol, 2 eq.) was added portionwise (3×) over 1.5 hrs (every 30 min). Thereaction was stirred overnight at room temperature. Ethyl acetate and 1N NaOH were added with thorough mixing and the organic layer wasseparated, dried with MgSO₄, filtered and evaporated to an oil. Theproduct was purified with flash chromatography (50:50/ethylacetate:hexane) to yield 48 as an oil. Compound 48, (mixture of cis andtrans stereoisomers) ¹H NMR (300 MHz, CDCl₃) δ6.64 (d, 2 h), 4.2 (m, 1H), 3.85 (m, 3 H, 3.75 (s, 6 H), 3.5 (m, 1 H), 3.1 (m, 2 H), 2.8 (m,2H), 2.55 (m, 1 H), 2.3 (m, 1 H), 1.7 (m, 3 H), 1.2 (m, 3 H).

EXAMPLE 7 Preparation of 5,8-Dimethoxy-2-[N-(L-alanyl methylester)-N-propyl]-3-methyl-1,2,3,4-tetrahydronaphthalene (47)

[0109] Compound 48 (0.28 g, 0.8 mmol) was dissolved in acetonitrilealong with propionaldehyde (0.1 mL, 1.6 mmol, 2 eq.) and acetic acid(0.2 mL, 1.6 mmol), and stirred for 1 hr at room temperature. One hourlater, sodium cyanoborohydride (0.2 g, 1.6 mmol, 2 eq.) was addedportionwise (3×) over a period of 1.5 hrs (every 30 minutes). Thereaction was stirred overnight at room temperature. Ethyl acetate and 1N NaOH were added to the reaction with thorough mixing and the organiclayer was separated, dried with MgSO₄, filtered and evaporated to anoil. This material was purified using flash chromatography (flashsilica, 80:20/hexane:ether) to afford (1:1 mixture of cis and transstereoisomers) 47.

[0110]¹H NMR (300 MHz, CDCl₃) δ6.6 (d, 2 H), 3.75 (s, 6 H), 3.7 (d, 4H), 3.0 (m, 2 H), 2.65 (m, 3 H), 2.2 (m, 1 H), 1.7 (m, 2 H), 1.45 (m, 2H), 1.25 (d, 3 H), 1.0 (m, 3 H), 0.8 (t, 3 H).

EXAMPLE 8 Preparation of5-Diphenylphosphinoyl-8-hydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthalene(58); and5,8-bis(Diphenylphosphinoyl)-3-methyl-1,2,3,4-tetrahydronaphthalene (59)

[0111] Compound 9 (0.5 g, 2.0 mmol) was dissolved in dioxane (100 mL) at0° C. Triethylamine (6 mL) was added and the reaction mixture wasstirred at 0° C. for 30 mins, followed by the addition ofdiphenylphosphinyl chloride (0.84 mL, 4.4 mmol). The reaction mixturewas stirred overnight at room temperature. NaHCO₃ and dichloromethanewere then added with thorough mixing. The organic layer was separated,dried with MgSO₄, filtered and the solvent was evaporated to a crude oilwhich was purified by flash chromatography (flash silica,70:30/hexane:ether) to yield 59 and 58. Compound 59: ¹H NMR (300 MHz,CDCl₃) δ7.85 (d, 4 H), 7.8 (d, 4 H), 7.5 (m, 12 H), 6.8 (q, 2 H), 3.0(m, 2 H), 2.4 (m, 7 H), 1.8 (m, 1 H), 1.4 (m, 4 H), 1.05 (d, 3 H), 0.85(t, 6 H). Compound 58 (1:1 mix of regioisomers): ¹H NMR (300 MHz, CDCl₃)δ7.85 (m, 4 H), 7.5 (m, 6 H), 6.6 (q, 1 H), 6.48 (s, 1 H), 6.21 (d, 1H), 2.9 (m, 3 H), 2.3 (m, 9 H), 1.65 (m, 1 H), 1.4 (m, 1 H), 1.05 (d, 3H), 0.85 (m, 6 H). In a similar manner, starting from 32, was preparedboth compounds 57 and 56. In addition, in a similar manner, startingfrom 9, was prepared compounds 49-51 using the appropriate reagents.

EXAMPLE 9 Preparation of5,8-Dimethoxy-cis-2-[N-(4-(2-(1-piperidinyl)ethoxy)phenyl)]amino-3-methyl-1,2,3,4-tetrahydronaphthalene(60)

[0112] A solution of 1-(2-chloroethoxy)-4-nitrobenzene (2.01 g, 0.01mol), piperidine (2.55 g, 0.03 mol), and toluene (10 mL) was refluxedovernight. The reaction mixture was filtered and the filtrate evaporatedto give 2.97 g of 1-[2-(1-piperidinyl)ethoxy]-4-nitrobenzene as anorange oil, MS M^(+ (m/e)) 251.18. This material (1.25 g, 0.004 mol) washydrogenated in ethanol (25 mL) in the presence of 10% Pd-C catalyst at40 psig and 25° C. overnight. Filtration and evaporation of the reactionmixture gave 0.95 g of 4-[2-(1-piperidinyl)ethoxy]aniline as a lightbrown oil, MS M^(+ (m/e)) 221.24. A solution of this oil (0.220 g, 1.0mmol), 3-methyl-5,8-dimethoxy-2-tetralone (6, 0.206, 0.94 mmol), and1,2-dichloroethane (3.5 mL) was treated with sodiumtriacetoxyborohydride (0.300 g, 1.4 mmol) and acetic acid (0.060 g, 1.0mmol) and the resulting mixture was stirred overnight at 25° C. Thereaction was treated with 3N sodium hydroxide solution with vigorousstirring. The organic layer was separated, washed with saturated sodiumchloride solution, dried over potassium carbonate, filtered andevaporated to a red oil. This material was purified by C-18 reversephase high pressure liquid chromatography affording compound 60 as apink solid. ¹H NMR (300 MHz, CDCl₃): δ7.10-7.22 (m, 2H), 6.52-6.82 (m,4H), 4.25-4.33 (m, 2H), 3.60-3.80 (m, 3H), 3.75 (s, 3H), 3.71 (s, 3H),3.48-3.38 (m, 2H), 2.80-3.05 (m, 4H), 1.80-2.10 (m, 4H), 1.10-1.50 (m,3H), 1.00 (d, 3H). MS M⁺ (m/e) 425.38.

[0113] The compounds shown in Table 1, below, were prepared according tothe procedures described herein. TABLE 1

MS M⁺ Cp. R₅ R₆ R₂ R₃ Config. (m/e) 9 H H Pr Pr trans 278.24 15 H H PrPr trans, 278.25 :. A 16 H H Pr Pr trans, 278.21 :. B 7 Me Me H Pr trans8 Me Me Pr Pr trans 306.28 17 Me Me Pr Pr trans, 306.24 :. A 18 Me Me PrPr trans, 306.27 :. B 19 Me Me Pr Ph(CH₂)₃ trans 382.28 20 H H PrPh(CH₂)₃ trans 354.27 21 Me Me Pr cC₆H₁₁CH₂ trans 360.32 22 H H PrcC₆H₁₁CH₂ trans 332.32 23 Me Me —(CH₂)₂O(CH₂)₂— cis 292.66 24 H H—(CH₂)₂O(CH₂)₂— cis 264.28 25 Me Me Pr CH₂Ph trans 354.74 26 H H PrCH₂Ph trans 326.21 27 Me Me Pr MeS(CH₂)₃ trans 352.29 28 H H PrMeS(CH₂)₃ trans 324.24 29 Me Me Pr (2-thienyl)CH₂ trans 360.24 30 H H Pr(2-thienyl)CH₂ trans 332.14 31 Me Me Pr CH₂CCH trans 302.21 32 H H PrCH₂CCH trans 274.16 33 Me Me Pr CH₂CCH cis 302.22 34 H H Pr CH₂CCH cis274.16 35 Me Me Pr CH₂(4-IPh) trans 480.11 36 H H Pr CH₂(4-IPh) trans452.14 37 Me Me Pr CH₂(4-BuOPh) trans 426.25 38 H H Pr CH₂(4-OHPh) trans342.16 39 Me Me Pr CH₂(2-ClPh) trans 388.18 40 H H Pr CH₂(2-ClPh) trans360.12 41 Me Me Pr CH₂(4-MePh) trans 368.29 42 H H Pr CH₂(4-MePh) trans340.18 43 H X Pr Pr trans 346.29 44 X H Pr Pr trans 346.30 45 Me H Pr Prtrans 292.22 46 H Me Pr Pr trans 292.22 47 Me Me Pr CH(Me)CO₂Me cis &350.26 trans 48 Me Me H CH(Me)CO₂Me cis & 308.19 trans 49 Y Y Pr Prtrans 446.39 50 H Y Pr Pr trans 362.26 51 Y H Pr Pr trans 362.30 52 MeMe Pr Me trans 278.19 53 H H Pr Me trans 250.18 54 Me Me Pr Z trans402.28 55 H H Pr Z trans 374.25 56 H X′ Pr CH₂CCH trans 474.13 57 X′ X′Pr CH₂CCH trans 674.11 58 H X′ Pr Pr trans 478.21 59 X′ X′ Pr Pr trans678.11 60 Me Me H Y′ cis 425.38

EXAMPLE 10

[0114] As a specific embodiment of an oral composition, 100 mg Compound9 from Example 1 is formulated with sufficient finely divided lactose toprovide a total amount of 580 to 590 mg to fill a size O hard gelcapsule.

EXAMPLE 11 Aβ₁₋₄₂ and Aβ₁₋₄₀ Binding to alpha-7 nAChRs can beDemonstrated in Competitive Binding Experiments with α-bungarotoxin

[0115] SK-N-MC cell membranes were incubated with 0.5 nM of¹²⁵I-α-bungarotoxin in the presence of various concentrations of Aβ₁₋₄₂and Aβ₁₋₄₀ at 25° C. for 1 hr. The assay mixture was then rapidlyfiltered and the radioactivity that was retained on the filter wasdetermined. These studies showed that both Aβ₁₋₄₂ and Aβ₁₋₄₀ inhibited¹²⁵I-α-bungarotoxin binding in a concentration-dependent manner withIC₅₀ values of 1 pM and 100 pM, respectively.

EXAMPLE 12 Aβ₁₋₄₂ Binding to alpha-7 nAChRs is Supported by CompetitiveBinding Experiments with ¹²⁵I-Aβ₁₋₄₀ and Provides a Seed for AmyloidDeposition and, thus, Incipient Plaque Formation

[0116] Alpha-7 nAChRs were immobilized on wheat germ agglutinin coupledyittrium SPA beads and allowed to incubate with ¹²⁵I-Aβ₁₋₄₀ in thepresence of various concentrations of cold Aβ₁₋₄₀ or Aβ₁₋₄₂. The datashowed that 0.1 femtoM of cold Aβ₁₋₄₂ completely abolished the binding,suggesting that Aβ₁₋₄₂ interacted with alpha-7 nAChRs with highaffinity. However, in the presence of 10 nM of cold Aβ₁₋₄₂ , the totalbinding of ¹²⁵I-Aβ₁₋₄₀ to alpha-7 nAChRs was dramatically increased. Weattribute this increase of binding at higher concentrations toAβ₁₋₄₂-induced precipitation of the Aβ peptides on the membranes.Prolonged incubation at lower concentrations also revealed that totalbinding was increased in reactions even with 100 pM of cold Aβ₁₋₄₂. Incontrol experiments, 80 pM ¹²⁵I-Aβ₁₋₄₀ did not bind appreciably, alongwith 1 pM to 1 nM of Aβ₁₋₄₀, to 30 μg of Bowes melanoma membranes. Thus,Aβ deposition can occur on biological cell membranes containing alpha-7nAChRs, but does not occur non-specifically on control membranes,suggesting that alpha-7 nAChRs can specifically seed the aggregation ofβ-amyloid in biological systems.

EXAMPLE 13 Aβ₁₋₄₂ Binding to alpha-7 nAChRs is of Higher Affinity thanAβ₁₋₄₀ Binding to alpha-7 nAChRs

[0117] Alpha-7 nAChRs were allowed to interact with Aβ₁₋₄₀ or Aβ₁₋₄₂ andthe mixture was then immunoprecipitated with anti-alpha-7 nAChRantibodies. Western analyses of the immunoprecipitated proteinsidentified only the presence of Aβ₁₋₄₂, indicating that theAβ₁₋₄₂/alpha-7 nAChR interaction is robust and of high affinity. Sinceit has already been shown that Aβ₁₋₄₀ binds to the alpha-7 receptor, thefailure in detecting Aβ₁₋₄₀ in this co-precipitation experiment suggeststhat the Aβ₁₋₄₀/alpha-7 nAChR interaction is of lower affinity than theAβ₁₋₄₂/alpha-7 nAChR interaction.

EXAMPLE 14 Compound 9 Inhibited Aβ Aggregation

[0118] Aβs are known to form aggregates leading to the formation ofamyloid plaques that are characteristic of Alzheimer's disease. Thisphenomenon can be demonstrated in vitro by using Synthaloid plates,coated with Aβ crystallization centers, and labelled Aβs for detectingaggregation. We have validated this aggregation assay using both¹²⁵I-Aβ₁₋₄₀ and fluo-Aβ₁₋₄₀ in a buffer containing 50 mM HEPES, pH 7.4,0.1% BSA, 10% FCS and protease inhibitors. About 500 pM of ¹²⁵I-Aβ₁₋₄₀or 100 nM of fluo-Aβ₁₋₄₀ in 100 μl of each well of the 96-wellSynthaloid plate was allowed to incubate for 2.5 hr at room temperaturein the presence or absence of inhibitors. At the end of the incubation,unbound protein in the wells was removed by three washes using the abovebuffer. The amount of bound protein which represented Aβ aggregation wasmeasured either by scintillation counting or fluorescence measurements.Compound 9 was found to potently inhibit Aβ aggregation with 10 nM IC₅₀.Time course studies also showed that prolonged incubation of amyloidaggregates with Compound 9 resulted in disaggregation.

[0119] Compounds which inhibit Aβ aggregation with an IC₅₀ <100micromolar may be effective in inhibiting the binding of Aβ to alpha-7in such a manner as to have a positive therapeutic effect useful for thetreatment of neurodegenerative disorders.

EXAMPLE 15 Compound 9 Blocked the Effect of Aβs on Acetylcholine Releasefrom Synaptosomes

[0120] Synaptosomes from guinea pig hippocampus were incubated with 0.1μM ³H-choline and then subjected to repeated washes to removeunincorporated ³H-choline. The synaptosomes were treated with 65 mMK^(+ for) 30 seconds to elicit 3H-acetylcholine release. While Aβ₁₋₄₀and Aβ₁₋₄₂ at 100 pM both inhibited acetylcholine release from thesepreparations (33% inhibition for both Aβ₁₋₄₀ and Aβ₁₋₄₂), pretreatmentof the synaptosomes with both 10 nM of Compound 9 and 100 pM of eitherAβ₁₋₄₀ and Aβ₁₋₄₂ prior to K⁺ stimulation was found to have no effect onacetylcholine release.

EXAMPLE 16 Compound 9 Inhibited ¹²⁵I-Aβ₁₋₄₀ Binding to alpha-7 nAChRs

[0121] To determine the effect of compound 9 on ¹²⁵I-Aβ₁₋₄₀ to alpha-7nAChRs, alpha-7 nAChR contained SK-N-MC cell membranes were immobilizedon wheat germ agglutinin coupled yittrium SPA beads and allowed toincubate with ¹²⁵I-Aβ₁₋₄₀ in the presence of various concentrations ofcompound 9. The result demonstrated that Compound 9 efficientlyinhibited the binding of ¹²⁵I-Aβ₁₋₄₀ to SK-N-MC cells with a 300 pMIC₅₀. Compounds which inhibit the binding of Aβ to alpha-7 nAChRs withan IC₅₀<1 micromolar may have a positive therapeutic effect useful forthe treatment of neurodegenerative disorders.

EXAMPLE 17 Assay for Peptide Binding to the 206-216 Stretch of the Humanα7 nAChR

[0122] A 2-5 ug quantity of the 11 amino acid peptide comprised of the206-216 stretch of the α7 nAChR (N-Ac, C(O)NH₂) are added to a 96-wellmicrotiter plate in 50 mL 10 mM HEPES, pH 7.4, or any buffer 50 ul.¹²⁵I-β-amyloid₁₋₄₀ (2000 Ci/mmol, 50 pM) was added to the wells in thepresence and absence of inhibitors (1 uM to 10 uM) dissolved in 1 uL of30% or 100% DMSO. Unbound ligands were removed and bound radioactivitywas measured using a Microbeta liquid scintillation counter. Ligandbinding can be inhibited by α-bungarotoxin, the peptide itself, andCompound 9.

[0123] Biological data for representative compounds of the presentinvention is provided in Table 2 which follows. TABLE 2 % ACh % α7Release NaChR at 10 μM % Inh Agg. 206-216 (IC₅₀, Cp. # (conc μM) BindingμM) 9 >90 (10) 94 94 (0.1) 15 50-90 (10) 85   (0.25) 16 50-90 (10) 44  (10) 7 50 (100) NT NT 8 50-90 (10) NT   (0.7) 17 >90 (10) NT 63 (1) 1850-90 (10) NT 70 (10) 19 30 (5) NT NT 20 39 (5) NT NT 21 20 (5) NT NT 2238 (50) NT NT 23 NT 54 NT 24 NT 43 NT 25 NT 48 NT 26 <30 (10) 64 NT 27NT NT NT 28 50-90 (10) 34 NT 29 12 (10) NT NT 30 38 (5) NT NT 31 34 (10)NT NT 32 69 (10) NT NT 33 NT NT NT 34 69 (10) NT NT 35 38 (10) NT NT 36<30 (10) NT NT 37 <30 (10) NT NT 38 <30 (10) NT NT 39 85 (10) NT NT 4075 (10) NT NT 41 <30 (10) 19 14 42 60 (10) NT NT 43 50-90 (10) 10  0 4450-90 (10) 23  0 45 30-50 (78) NT 78 46 50-90 (10) 18  0 47 NT NT NT 48<30 (10) 2  0 49 50-90 (10) 0 17 50 <30 (10) 0 67 51 30-50 (10) 0 54 5260 (10) 0  0 53 50-90 (10) 0 18 54 50-90 (10) 0  0 55 50-90 (10) 0 15 56<30 (10) 78  8 57 <30 (10) 63 11 58 <30 (10) 42 18 59 <30 (10) 72 25 60very 0 24 active

[0124] While the foregoing specification teaches the principals of thepresent invention, with examples provided for the purpose ofillustration, it will be understood that the practice of the inventionencompasses all of the usual variations, adaptations and/ormodifications as come within the scope of the following claims and theirequivalents.

What is claimed is:
 1. A method of treating a neurodegenerative disorderin a subject in need thereof which comprises administering to thesubject an amount of a compound effective to inhibit the binding of anamyloid beta peptide with alpha-7 nicotinic acetylcholine receptors. 2.The method of claim 1, wherein the alpha-7 nicotinic acetylcholinereceptors are human alpha-7 nicotinic acetylcholine receptors.
 3. Themethod of claim 2, wherein the neurodegenerative disorder is selectedfrom Alzheimer's disease, Pick's disease, diffuse Lewy body disease,progressive supranuclear palsy (Steel-Richardson syndrome), multisystemdegeneration (Shy-Drager syndrome), motor neuron diseases includingamyotrophic lateral sclerosis, degenerative ataxias, cortical basaldegeneration, ALS-Parkinson's-Dementia complex of Guam, subacutesclerosing panencephalitis, Huntington's disease, Parkinson's disease,synucleinopathies, primary progressive aphasia, striatonigraldegeneration, Machado-Joseph disease/spinocerebellar ataxia type 3 andolivopontocerebellar degenerations, Gilles De La Tourette's disease,bulbar and pseudobulbar palsy, spinal and spinobulbar muscular atrophy(Kennedy's disease), primary lateral sclerosis, familial spasticparaplegia, Werdnig-Hoffmann disease, Kugelberg-Welander disease,Tay-Sach's disease, Sandhoff disease, familial spastic disease,Wohlfart-Kugelberg-Welander disease, spastic paraparesis, progressivemultifocal leukoencephalopathy, and prion diseases (includingCreutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker disease, Kuru andfatal familial insomnia, age-related dementia, vascular dementia,diffuse white matter disease (Binswanger's disease), dementia ofendocrine or metabolic origin, dementia of head trauma and diffuse braindamage, dementia pugilistica or frontal lobe dementia, neurodegenerativedisorders resulting from cerebral ischemia or infaction includingembolic occlusion and thrombotic occlusion as well as intracranialhemorrhage of any type, intracranial and intravertebral lesions,hereditary cerebral angiopathy, nonneuropathic hereditary amyloid,Down's syndrome, macroglobulinemia, secondary familial Mediterraneanfever, Muckle-Wells syndrome, multiple myeloma, pancreatic- andcardiac-related amyloidosis, chronic hemodialysis arthropathy, orFinnish and Iowa amyloidosis.
 4. The method of claim 3, wherein theamyloid beta peptide is Aβ₁₋₄₂.
 5. The method of claim 3, wherein theneurodegenerative disorder is Alzheimer's disease.
 6. The method ofclaim 5, wherein the compound inhibits the binding of Aβ₁₋₄₂ with thehuman alpha-7 nicotinic acetylcholine receptor by binding to Aβ₁₋₄₂. 7.The method of claim 3, wherein the compound inhibits the binding ofAβ₁₋₄₂ with the human alpha-7 nicotinic acetylcholine receptor bybinding to human alpha-7 nicotinic acetylcholine receptors.
 8. Themethod of claim 3, wherein the compound inhibits the binding of Aβ₁₋₄₂with the human alpha-7 nicotinic acetylcholine receptor by inhibitingaggregation of amyloid beta peptides.
 9. The method of claim 5, whereinthe compound is of the formula I

wherein R₁ is hydrogen or C₁-C₄ alkyl; R₂ is selected from hydrogen,C₁-C₆ alkyl, aryl or C₇-C₁₀ aralkyl; R₃ is selected from hydrogen, C₁-C₆alkyl, C₃-C₁₀ alkenyl, C₃-C₈ cycloalkylC₁-C₆ alkyl, C₁-C₆alkoxycarbonylC₁-C₆ alkyl, C₁-C₆ alkylthio, heteroarylC₁-C₄ alkyl,unsubstituted or substituted aryl or unsubstituted or substituted C₇-C₁₀aralkyl wherein the substituent on the aryl or aralkyl are one or moresubstituents independently selected from the group consisting ofhalogen, hydroxy, C₁-C₆ alkyl and unsubstituted or substituted C₁-C₆alkoxy wherein the substituents on the alkoxy are one or moresubstituents independently selected from amino, C₁-C₆ alkylamino, C₁-C₆dialkylamino, pyrrolidinyl, piperidinyl, azepinyl or morpholinyl; or R₂and R₃, together with the nitrogen to which they are attached, form afive or six-membered heterocyclic ring selected from pyrrolidinyl,piperidinyl, morpholinyl, thiomorpholinyl or piperazinyl; R₄ is C₁-C₆alkyl, aryl, or C₇-C₁₀ aralkyl; and R₅ and R₆ are each independentlyselected from hydrogen, C₁-C₆ alkyl, C₃-C₁₀ alkenyl, C₁-C₈alkylcarbonyl, or diphenylphosphinyl; and pharmaceutically acceptablesalts and prodrugs thereof.
 10. A method of treating and/or preventingdementia in an Alzheimer's disease patient which comprises administeringto the subject a therapeutically effective amount of a compound whichinhibits the binding of an amyloid beta peptide with alpha-7 nicotinicacetylcholine receptors.
 11. The method of claim 10, wherein the amyloidbeta peptide is Aβ₁₋₄₂ and the alpha-7 nicotinic acetylcholine receptorsare human alpha-7 nicotinic acetylcholine receptors.
 12. The method ofclaim 11, wherein the compound is of the formula I

wherein R₁ is hydrogen or C₁-C₄ alkyl; R₂ is selected from hydrogen,C₁-C₆ alkyl, aryl or C₇-C₁₀ aralkyl; R₃ is selected from hydrogen, C₁-C₆alkyl, C₃-C₁₀ alkenyl,C₃-C₈ cycloalkylC₁-C₆ alkyl, C₁-C₆alkoxycarbonylC₁-C₆ alkyl, C₁-C₆ alkylthio, heteroarylC₁-C₄ alkyl,unsubstituted or substituted aryl or unsubstituted or substituted C₇-C₁₀aralkyl wherein the substituent on the aryl or aralkyl are one or moresubstituents independently selected from the group consisting ofhalogen, hydroxy, C₁-C₆ alkyl and unsubstituted or substituted C₁-C₆alkoxy wherein the substituents on the alkoxy are one or moresubstituents independently selected from amino, C₁-C₆ alkylamino, C₁-C₆dialkylamino, pyrrolidinyl, piperidinyl, azepinyl or morpholinyl; or R₂and R₃, together with the nitrogen to which they are attached, form afive or six-membered heterocyclic ring selected from pyrrolidinyl,piperidinyl, morpholinyl, thiomorpholinyl or piperazinyl; R₄ is C₁-C₆alkyl, aryl, or C₇-C₁₀ aralkyl; and R₅ and R₆ are each independentlyselected from hydrogen, C₁-C₆ alkyl, C₃-C₁₀ alkenyl, C₁-C₈alkylcarbonyl, or diphenylphosphinyl; and pharmaceutically acceptablesalts and prodrugs thereof.
 13. A method of improving memory and/or ofhalting the progression of mental deterioration in an Alzheimer'sdisease patient which comprises administering to the subject atherapeutically effective amount of a compound to inhibit the binding ofan amyloid beta peptide with alpha-7 nicotinic acetylcholine receptors.14. The method of claim 13, wherein the amyloid beta peptide is Aβ₁₋₄₂and the alpha-7 nicotinic acetylcholine receptors are human alpha-7nicotinic acetylcholine receptors.
 15. The method of claim 14, whereinthe compound is of the formula I

wherein R₁ is hydrogen or C₁-C₄ alkyl; R₂ is selected from hydrogen,C₁-C₆ alkyl, aryl or C₇-C₁₀ aralkyl; R₃ is selected from hydrogen, C₁-C₆alkyl, C₃-C₁₀ alkenyl, C₃-C₈ cycloalkylC₁-C₆ alkyl, C₁-C₆alkoxycarbonylC₁-C₆ alkyl, C₁-C₆ alkylthio, heteroarylC₁-C₄ alkyl,unsubstituted or substituted aryl or unsubstituted or substituted C₇-C₁₀aralkyl wherein the substituent on the aryl or aralkyl are one or moresubstituents independently selected from the group consisting ofhalogen, hydroxy, C₁-C₆ alkyl and unsubstituted or substituted C₁-C₆alkoxy wherein the substituents on the alkoxy are one or moresubstituents independently selected from amino, C₁-C₆ alkylamino, C₁-C₆dialkylamino, pyrrolidinyl, piperidinyl, azepinyl or morpholinyl; or R₂and R₃, together with the nitrogen to which they are attached, form afive or six-membered heterocyclic ring selected from pyrrolidinyl,piperidinyl, morpholinyl, thiomorpholinyl or piperazinyl; R₄ is C₁-C₆alkyl, aryl, or C₇-C₁₀ aralkyl; and R₅ and R₆ are each independentlyselected from hydrogen, C₁-C₆ alkyl, C₃-C₁₀ alkenyl, C₁-C₈alkylcarbonyl, or diphenylphosphinyl; and pharmaceutically acceptablesalts and prodrugs thereof.
 16. A method for identifying compounds whichare useful for the treatment of neurodegenerative disorders involvingscreening test compounds for their ability to block the interaction of apeptide selected from the group consisting of ¹²⁵I-Aβ₁₋₄₀, Aβ₁₋₄₀ andAβ₁₋₄₂ with nicotine acetylcholine receptors.
 17. The method of claim16, wherein the nicotine acetycholine receptors are human alpha-7, humanalpha-8, and/or human alpha-9 nicotinic acetylcholine receptors.
 18. Themethod of claim 17, wherein the nicotine acetylcholine receptors arehuman alpha-7 nicotine acetylcholine receptors.
 19. The method of claim18, wherein the peptide is ¹²⁵I-Aβ₁₋₄₀.
 20. A compound of the formula I:

wherein R₁ is hydrogen or C₁-C₄ alkyl; R₂ is selected from hydrogen,C₁-C₆ alkyl, aryl or C₇-C₁₀ aralkyl; R₃ is selected from hydrogen, C₁-C₆alkyl, C₃-C₁₀ alkenyl, C₃-C₈ cycloalkylC₁-C₆ alkyl, C₁-C₆alkoxycarbonylC₁-C₆ alkyl, C₁-C₆ alkylthio, heteroarylC₁-C₄ alkyl,unsubstituted or substituted aryl or unsubstituted or substituted C₇-C₁₀aralkyl wherein the substituent on the aryl or aralkyl are one or moresubstituents independently selected from the group consisting ofhalogen, hydroxy, C₁-C₆ alkyl and unsubstituted or substituted C₁-C₆alkoxy wherein the substituents on the alkoxy are one or moresubstituents independently selected from amino, C₁-C₆ alkylamino, C₁-C₆dialkylamino, pyrrolidinyl, piperidinyl, azepinyl or morpholinyl; or R₂and R₃, together with the nitrogen to which they are attached, form afive or six-membered heterocyclic ring selected from pyrrolidinyl,piperidinyl, morpholinyl, thiomorpholinyl or piperazinyl; R₄ is C₁-C₆alkyl, aryl, or C₇-C₁₀ aralkyl; and R₅ and R₆ are each independentlyselected from hydrogen, C₁-C₆ alkyl, C₃-C₁₀ alkenyl, C₁-C₈alkylcarbonyl, or diphenylphosphinyl; and pharmaceutically acceptablesalts and prodrugs thereof.
 21. The compound of claim 20, wherein R₁ ishydrogen; R₂ is selected from hydrogen or C₁-C₄ alkyl; R₃ is selectedfrom C₁-C₄ alkyl, C₃-C₁₀ alkenyl, C₅-C₆ cycloalkylC₁-C4 ₆ alkyl, C₁-C₆alkoxycarbonylC₁-C₄ alkyl, C₁-C₆ alkylthio, heteroarylC₁-C₄ alkyl, orunsubstituted or substituted C₇-C₁₀ aralkyl wherein the substituent onthe aralkyl are one or two substituents independently selected from thegroup consisting of halogen, hydroxy, C₁-C₄ alkyl and unsubstituted orsubstituted C₁-C₄ alkoxy wherein the substituents on the alkoxy are oneor two substituents independently selected from amino, C₁-C₄ alkylamino,C₁-C₄ dialkylamino, pyrrolidinyl, or piperidinyl; or R₂ and R₃, togetherwith the nitrogen to which they are attached, form a morpholinyl ring;R₄ is C₁-C₄ alkyl; and R₅ and R₆ are each independently selected fromhydrogen, C₁-C₄ alkyl, C₃-C₆ alkenyl, C₁-C₆ alkylcarbonyl, ordiphenylphosphinyl; and pharmaceutically acceptable salts and prodrugsthereof.
 22. The compound of claim 20 of the formula

wherein R₁ is hydrogen or C₁-C₄ alkyl; R₂ and R₃ are each independentlyselected from hydrogen, C₁-C₆ alkyl, aryl or C₇-C₁₀ aralkyl; and R₄ isC₁-C₆ alkyl, aryl, or C₇-C₁₀ aralkyl; and pharmaceutically acceptablesalts and prodrugs thereof.
 23. A compound of claim 22 which is5,8-dihydroxy-trans-2-di(N-propylamino)-3-methyl-1,2,3,4-tetrahydronaphthaleneand pharmaceutically acceptable salts and prodrugs thereof.
 24. Apharmaceutical composition comprising a pharmaceutically acceptablecarrier and a compound of claim
 20. 25. A pharmaceutical compositionmade by mixing a compound of claim 20 and a pharmaceutically acceptablecarrier.
 26. A process for making a pharmaceutical compositioncomprising mixing a compound of claim 20 and a pharmaceuticallyacceptable carrier.
 27. A method for diagnosing Alzheimer's disease,monitoring the progression and prognosis of Alzheimer's disease and/ormonitoring the therapeutic efficacy of any intervention or treatment ofAlzheimer's disease comprising: (a) obtaining a test sample from asubject wherein the test sample comprises circulating blood cells and/orolfactory neuroepithelial neuronal cell bodies or their neuronalprocesses; and (b) analyzing the test sample for interaction of anamyloid beta peptide with alpha-7 nicotinic acetylcholine receptors.